Our top recommendation for a timber wall structure is what we call a Nordic Wall. A Nordic Wall achieves the desired U-value with a thinner structure compared to other timber structures. A ventilation gap behind the timber cladding allows good ventilation level. Therefore we recommend the use of wind protection insulation, such as PAROC WPS 3n or PAROC WPB 3n on top of the studs as external continuous thermal insulation layer. This continuous layer significantly reduces cold bridges and the amount of moisture on the timber studs. The seams of wind protection slabs have to be tightened with tape (PAROC XST 020 or PAROC XST 021). The inside air tightness is ensured with sealed air/ vapour barrier. Both inside and outside air tightness is essential in this type of structure.

Internal surface: plaster board

Studding cc 600 / PAROC eXtra

Air/vapour barrier

Timber frame cc 600 / PAROC eXtra

Wind protection insulation: PAROC WPS 3n or PAROC WPB 3n

Taped seams: PAROC XST 020

Spacer + ventilation gap ≥ 20mm

Timber cladding

Insulation solution with U value

PAROC eXtra (studding)

50 mm

50 mm

PAROC eXtra (frame)

175 mm

200 mm

PAROC WPS 3n

55 mm

55 mm

U-value, W/m2K

0.13

0.12

The Nordic Wall with brick lining provides an excellent solution for the extreme conditions of Nordic winters. The challenge with this structure is that a brick wall absorbs water – the water may even be transferred through the whole brick lining. To keep water away from the insulation, a proper ventilation gap is needed. The gap must be solid, open and finless. A brick facade keeps the air movement in the ventilation gap at a lower level than with timber cladding. To ensure proper ventilation of the structure, leave every third vertical seam of the second lowest layer of bricks open. Design the wall so that penetrating water can be led out from the structure.

In passive houses the walls have to be even more effective. This innovative double timber frame practically eliminates cold bridges and reduces the overall wall thickness too. In the middle of this structure, the un-framed insulation layer is flexible in thickness, making this solution suitable for various u-value requirements.

Additional internal studding inside the vapour barrier is essential. Install electricity and water pipes to the studding without breaking the vapour barrier.

Structure:

Internal facing

Studding / PAROC eXtra (d1) (installation space)

Vapour barrier (all joints to be taped)

PAROC eXtra (d2)

Supporting structure: timber frame / PAROC eXtra (d3)

PAROC WPS 3n (or PAROC Cortex) (d4)

Spacer / ventilation gap 20 mm

Cladding

Small houses

Recommended U value

W/m2K

0.07 - 0.10

d1

mm

75

d2

mm

125 - 250

d3

mm

125

d4

mm

50

Total insulation thickness

mm

375 - 500

I-joist frames reduce cold bridges on the wall structure and the amount of moisture in joists compared to normal timber frame wall.

Structure:

Internal facing

Studding/ PAROC UNS 37 (d1) (installation space)

Vapour barrier (all joints to be taped)

Supporting structure; I-Joist / PAROC eXtra (d2)

PAROC WAS 25t (d3)

Spacer / ventilation gap 30mm

Brick facade

Small houses

Recommended U value

W/m2K

0.07 - 0.10

d1

mm

50

d2

mm

270 - 350

d3

mm

50

Total insulation thickness

mm

370 - 450

Notes:
According to the definition of a passive house provided by the Passive House Institute, the annual heating, cooling and primary energy demand should not exceed certain values. Although good thermal insulation plays a major role in achieving the Passive House standard, it alone cannot ensure compliance. The requirements for other building components and devices can be determined by various calculations tools, such as the Passive House Planning Package (PHPP), available at www.passiv.de.

When a single timber frame is not enough, a cross-studding wall is typically the recommendation. However, a Nordic Wall is often the more economical solution and provides better thermal resistance. The horizontal cross-laid secondary studs can also be mounted to the interior side of the wall.

If you install the cross studding to the interior side of the wall, then place the vapour barrier between the load bearing timber frame and the studding. This structure is more air tight, because it allows electricity cables to be installed inside the vapour barrier without through holes.

This basic form of ventilated timber wall contains only the essential components of a layered wall structure. Install the insulation to the timber frame and make wind protection using plaster board with sealed seams. The ventilation gap is usually formed with 22x100mm timber set horizontally or with cross-laid double frame depending on the direction of the timber cladding.

Timber frames 48 x 48/150/175/200 mm, cc 600
The effect of the mechanical fasteners is less than 3 %, meaning there is no need for correction.

As a pioneer in the insulation industry Paroc aims to fulfil the changing demands today’s world sets for the environments we build for ourselves. Sustainable and durable choices can ensure fire safe, energy-efficient and comfortable living and working environments in the future. Our reliable solutions and unique ability to innovate encourage others to follow us. By staying ahead of the competition and achieving growth, we can ensure the development of our solutions, operations, and employees. We are open in our operations as we think that by inspiring others we can shape the entire construction industry.